A Comprehensive Analysis Process for Vehicle Impact-Harshness Performance Assessment

摘要

Impact Harshness (IH) describes sound and vibration response experienced by vehicle occupants resulting from tire interactions with various road discontinuities such as bumps, potholes, etc. at low vehicle speeds. Undesirable impact harshness performance of a vehicle leads to perception of poor Noise, Vibration and Harshness (NVH) performance and quality resulting in negative customer feedback. In this paper, the authors present development of a comprehensive Multi-Body Dynamics (MBD) full vehicle analytical model of a minivan to simulate a vehicle driven over a cleat at 30 Kph and predict the tactile response at the customer touch points (e.g. seat track). The MBD model includes flexible body and chassis structure along with accurate frequency dependent stiffness and damping representation of powertrain mounts and all major bushings in the vehicle. The analytical model was correlated and validated with test data. The validated model was then utilized to improve the IH performance through design modifications. The veracity of the improved design was confirmed with vehicle test. While the analytical model was validated with test data, the developed process is intended to be more of a directional tool allowing an engineer to quickly compare multiple design proposals and provide design direction for improved IH performance.